More than 500 hours of secret tape recordings recorded in the White House by former President Richard Nixon have been released by the US national archives.

I'd rather use the nuclear bomb...I just want you to think big

Richard Nixon

The 1,000 tapes, recorded in the first six months of 1972, the last year of Nixon's first presidency, give new insight into the disgraced president's attempts to cover up the Watergate scandal, his handling of the Vietnam and his historic visit to China.

At times sounding muffled, Nixon can nevertheless clearly be heard discussing foreign affairs with political aides such as then-national security adviser Henry Kissinger.

Issues ranged from the most mundane day-to-day activities to the possibility of dropping a nuclear bomb on Vietnam, which the pair debated in April 1972.

Vietnam

"I'd rather use the nuclear bomb," Nixon is heard to say in a matter-of-fact tone.

The tapes include discussions Nixon's historic 1972 visit to China

"That, I think, would just be too much," Kissinger replies cautiously.

"Does that bother you?" Nixon is heard to reply sharply, adding, "I just want you to think big."

A later conversation taped in June the same year with domestic adviser Charles Colson reveals an extremely angry Nixon gruffly dismiss Vietnam.

"We want to decimate the goddamn place," he barks to Mr Colson.

"North Vietnam is going to get reordered...it's what should have been done a long time ago."

Secret Taiwan concession

The transcripts also show Mr Kissinger conceded China's territorial claim over Taiwan during his secret visit to Beijing in July 1971.

He admitted to the then Chinese Prime Minister Zhou Enlai that had the Korean war not intervened, Taiwan would probably be part of China.

He said that long-term, Washington would not stand in the way of it becoming so again.

But he asked China not to rush the United States into making formal declarations.

The records also show that before the meeting, President Nixon told Mr Kissinger that he should not show until necessary that America might be willing to abandon its support for Taiwan.

President Nixon also told Mr Kissinger to emphasise the threat of a militarily resurgent Japan if American troops pulled out of the region.

In his memoirs, Mr Kissinger had said the Taiwan issue had hardly been discussed at his meeting with Mr Chou.

Watergate scandal

Nixon ordered his secret service agents to install tape recording equipment in the White House and they captured everything said in the Oval Office and cabinet room.

The infamous Watergate scandal that eventually forced Nixon from office is also captured in its entirety, including the infamous "smoking gun" snippet, where Nixon discusses using the Central Intelligence Agency (CIA) to try and thwart the FBI's investigation of the case.

The conversations form the largest release so far by the national archives.

It also marks the first time that historians and researchers have been able to use their own recording equipment to copy the tapes.